Use is known in the packaging sector of packaging machines which form part of a system which is able to automatically place products, such as food products but also other products, in envelopes and boxes, using automatic packaging lines.
The products to be packaged are automatically sent towards packaging lines which use horizontal or vertical packaging machines, of the flow-pack and HFFS type (horizontal form fill seal), which make closed packs, generally with three seals, of various products mainly loose, such as grated cheese, mozzarella pearls, dog pellets and pasta, with vertical loading, starting from a reel of hot or cold sealing wrapping material consisting of a flexible film.
The packaging machines may in general also be very different from each other, but all have in common the aim of placing the product in envelopes, starting from a reel of heat-sealing wrapping material, and conveying it towards the boxing sector.
One of the problems encountered with the use of these packaging machines regards the possibility of having to package batches of products of different size which can be placed in packages having differing dimensions from one size to the other.
This possibility, which is also very common especially in the case of various loose products such as grated cheese, mozzarella pearls, dog pellets and pasta, which are loaded vertically, results in some practical difficulties, during the steps for changing the format of the envelopes, as on one hand it is necessary to use skilled personnel working manually and even with lengthy process times, and on the other hand there is a certain degree of imprecision in the setting up of the formats.
In effect, traditional packaging machines, especially those with a high productivity, are equipped with a plurality of the forming, welding, cutting and pulling groups, which, in the event of change of size of the envelope used for the packaging, due, precisely, to the change of size of the product to be packaged, must be moved one at a time to change from the dimensions of the previous format to that necessary for to the subsequent working.
In some cases, certain automatic devices are used with the aim of mechanising the changeover process, however their efficiency has been found to be rather limited and poor, and not able to guarantee the necessary precision.
Currently, in effect, some manufacturers install, for example, a system with a relatively simple design for movement of the various stations and only for a limited number of stations, typically those for welding.
The system for movement of the stations which is used in some cases connects the movable stations with a single “drive unit”, for example a threaded bar, which moves them simultaneously so as to modify the spacing.
A problem found using this solution is the fact that the movement is only relative between one station and the other and it is not possible to move a single station.
This represents a significant limitation since small adjustments on the individual stations are not allowed in order to correct the inevitable imprecisions of the packaging machines.
A further problem found is that relative to the limited effectiveness, since this type of semi-automatic adjustment is applicable to a limited number of stations since they must be interconnected by the drive unit.